List<Feature<?>> allFeatures =
        Arrays.<Feature<?>>asList(
            CollectionSize.ANY,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION,
            CollectionFeature.GENERAL_PURPOSE,
            CollectionFeature.REMOVE_OPERATIONS,
            CollectionFeature.SERIALIZABLE,
            CollectionFeature.KNOWN_ORDER,

  ALLOWS_ANY_NULL_QUERIES(
      ALLOWS_NULL_ENTRY_QUERIES, ALLOWS_NULL_KEY_QUERIES, ALLOWS_NULL_VALUE_QUERIES),
  RESTRICTS_KEYS,
  RESTRICTS_VALUES,
  SUPPORTS_PUT,
  SUPPORTS_REMOVE,
  FAILS_FAST_ON_CONCURRENT_MODIFICATION,
  /**
   * Indicates that the constructor or factory method of a map, usually an immutable map, throws an
   * {@link IllegalArgumentException} when presented with duplicate keys instead of discarding all
   * but one.

   */
  REJECTS_DUPLICATES_AT_CREATION,

  SUPPORTS_ADD,
  SUPPORTS_REMOVE,
  SUPPORTS_ITERATOR_REMOVE,
  FAILS_FAST_ON_CONCURRENT_MODIFICATION,

  /**
   * Features supported by general-purpose collections - everything but {@link #RESTRICTS_ELEMENTS}.
   *
   * @see java.util.Collection the definition of general-purpose collections.
   */

 * IteratorTester#newTargetIterator()} method. This is because it's impossible to test an Iterator
 * without changing its state, so the tester needs a steady supply of fresh Iterators.
 *
 * <p>If your iterator supports modification through {@code remove()}, you may wish to override the
 * verify() method, which is called after each sequence and is guaranteed to be called

  @Override
  public int count(@CheckForNull Object element) {
    Count frequency = Maps.safeGet(backingMap, element);
    return (frequency == null) ? 0 : frequency.get();
  }

  // Optional Operations - Modification Operations

  /**
   * {@inheritDoc}
   *
   * @throws IllegalArgumentException if the call would result in more than {@link
   *     Integer#MAX_VALUE} occurrences of {@code element} in this multiset.
   */

  private int hashTableMask() {
    return (1 << (metadata & CompactHashing.HASH_TABLE_BITS_MASK)) - 1;
  }

  void incrementModCount() {
    metadata += CompactHashing.MODIFICATION_COUNT_INCREMENT;
  }

  @CanIgnoreReturnValue
  @Override
  public boolean add(@ParametricNullness E object) {
    if (needsAllocArrays()) {
      allocArrays();
    }

    this.inverse = inverse;
  }

  // Query Operations (optimizations)

  @Override
  public boolean containsValue(@CheckForNull Object value) {
    return inverse.containsKey(value);
  }

  // Modification Operations

  @CanIgnoreReturnValue
  @Override
  @CheckForNull
  public V put(@ParametricNullness K key, @ParametricNullness V value) {
    return putInBothMaps(key, value, false);
  }

   * concurrent modification, the iterator fails quickly and cleanly, rather than risking arbitrary,
   * non-deterministic behavior at an undetermined time in the future.
   *
   * <p>Note that the fail-fast behavior of an iterator cannot be guaranteed as it is, generally
   * speaking, impossible to make any hard guarantees in the presence of unsynchronized concurrent

        E element = entry.getElement();
        for (int i = entry.getCount(); i > 0; i--) {
          list.add(element);
        }
      }
      return list;
    }

    // Modification Operations

    /**
     * Adds a number of occurrences of the specified element to this multiset.
     *
     * @param element the element to add
     * @param occurrences the number of occurrences to add

        assertTrue(greater + ".compareTo(" + t + ')', greater.compareTo(t) > 0);
        assertFalse(greater.equals(t));
      }
    }
  }

  /**
   * Returns a collection that simulates concurrent modification by having its size method return
   * incorrect values. This is useful for testing methods that must treat the return value from
   * size() as a hint only.
   *